Process for the production of anhydrous hydrocarbon derivatives



` Nov, 30, 1937. w. ENGS Er AL PROCESS FOR THE PRODUCTION OF ANHYDROUS HYDROCARBON DERIVATIVES Filed oct'. 15, 1936 Patented Nov. 30, 1937 UNITED i' STATES PROCES-S FOR THE PRODCTION OF `AN- HYDBOUS HYDRQCARBON DERIVATIVES William Engs, Oakland, and Gerald Henry van de Griendt, Berkeley, Calif assignors to Shell Development Company, San Francisco, Calif., a corporation of Delaware Application October 13, 1936, Serial No. 105,394

11 Claims.

This invention relates to the manufacture .of oxygen containing organic compounds such as a1- cohols, ethers, acids and esters from hydrocar bons. The process is particularly adapted for the 5 production of secondary and/or tertiary alcohols, or other derivatives from oienes having four or more carbon atoms per molecule.

The primary object of the present invention is to eiiiciently and economically produce such compounds in an anhydrous forni. In accordance with this object, water is separated from the alcohols or other derivatives, produced without the yaddition of any extraneous agents tol the system as these require a separate puriiication step for their removal -from the normal distillation products.

A further object of the invention is the provision of a process of dehydrating oxygen containing oleilne derivatives by distillation, or extraction and distillation, with the rhydrocarbon used in their manufacture.

Still another object of the invention is the production of derivatives of olenes of four or more carbon atoms by a method which permits recovery of regenerated and/or unreacted olefine and its return to the reaction system in a simple, uniform manner so that constant composition of feed may be maintained without recourse to elabcrate proportioning devices or other expensive procedures.

Y Various methods for dehydrating alcohols and related olefine derivatives, many of which form constant boiling mixtures with water or for other reasons are dimcult to obtain in a pure anhydrous condition, havebeen proposed in which a third agent, such, for example, as benzol. is used to assist in the removal of Water by azeotropic distillation. All prior alcohol dehydration methods have the drawback, however, that they require a separate distillation step to prevent contamination of the olelne regenerated in the recovery process by the added third agent.

We have found that not onlyl may this extra distillation be avoided but also the oleiine re- 45 action itself may be improved by usinga procedure in which dehydration is eected by means of the same olene containing hydrocarbon as is usedior the production of the olene derivative or derivatives being treated. i

In order that our invention may be clearly understood it will be more fully described with reference vto the accompanying drawing which is a diagrammatic representation of the steps of our process inone oi its modications' applied to the' 5.5 manufacture of tertiary amyl alcohol by absorb` tion of tertiary amylenes in aqueous sulfuric acid. It will be understood that other olenes having four or more carbon atoms per molecule, such for example, as isobutylene and/or butene-l yand butene-Z or pentene-l and pentene-2 and higher 5 homologues may also' be used provided suitable adjustment of operating conditions in accordance with the known differences in character of these olenes are made. Anysuch olenes may be used either in a pure state as the chemical indi- 10 viduals or as pure olenic mixtures or as an olene or olenes admixedwith one or more paraiiinic hydrocarbons or other compounds which may be considered as inert in the alcohol manuiacturing process. Oleiinescomprising hydrocar- 15 I bon fractions consisting` of, or predominating in,

vhydrocarbons containing the same numberv of carbons atoms to the molecule are a particularly advantageous starting material for the process of our invention.

'In the drawing, i represents a source of a pen- 20 vtane-aniylene fraction which may, for example,

have the following approximate composition: pentanes 41%, secondary amylenes 37% and tertiary amylenes 22%. This hydrocarbon niixturev 25 is withdrawn thru pipe line 2 and admixed-in pipe 3 with the crude, wet tertiary amyl alcohol being. produced. The mixing may be facilitated by feeding the two materials thru a centrifugal pump or by other suitable means not shown. 30 After mixing the materials are conducted to a separator such as d where two layers are formed,

an aqueous layer containing in this. case about 80% of the total water in the wet tertiary amyl alcohol which is removed thru line d and returned 35 to the processas will be explained later, and a hydrocarbon layer containing the bulk of the tertiary amyl alcohol and the remaining water, which is fed by line 6 to a fractiohating column 7. From this column a completely dehydrated bot- 'tom' product of tertiary amyl alcohol may be withdrawn thru line o and redistilled in any suitable manner, not shown. to remove any remaining impuritiesV such, for example, as small amounts of polymer. This dehydration is eiected by distilling overhead the pentane-amylne as there is more vthan enough. hydrocarbon p res ent to remove the Water remaining after vextracf ti'on as the binary azeotropes oi amylene and pentane with water.

The overhead product is condensed in con denser t, cooled by a suitable refrigerant circulated therethrough by means of inlet and out--l let lines 85 and 36, vand stratified in-separator I0. The aqueous layer is removed via line Il and combined with the previously mentioned aqueous layer from separator 4. The hydrocarbon layer is removed by line II to reux accumulator I2 y, system is'taken by line I5- to an intermediate storage tank such as I6.

. The pentane-amylene feed from tank I6 is admixed with HzSOi from tank I8. -Other suitable mineral acid acting acid such as, for example, phosphoric, benzene sulfonic acid, or the like, of a concentration adapted in the known manner to the nature and concentration of the olefine or olefines being treated, maybesubstituted for sulfuric acid. The acid-hydrocarbon mixture is fed to a reactor I9, preferably provided with temperature controlling means whereby the temperature may be maintained within the range known to be suitable for the particular olene's and acid involved. A temperature of from 0 to about 30 C. is suitable for the selective absorption of tertiary amylenes under the conditions here described, for example. The reactants are withdrawn from the reactor to a separator 20 at arate which permits sufficient time of contact for the desired reaction, 10 to 20 minutes contact, for example, is sufficient in the present case'.

`Unreacted hydrocarbon comprising principally pentanes and secondary amylenes is taken off as upper layer thru line 2|` and acid layer is withdrawn thru line 22. A part of the withdrawn acid layer may advantageously be returned to the reactor via -line 23, if desired.' The remaining withdrawn acid layer is fed to a dilution tank 24 Where it is mixed with the water recovered from separators 4, I0 and 3|. Additional water such as may be necessary to replace losses and bring the mixture to the desired acid concentration for distillation, a sulfuric acid concentration of about 20% to 30% on a hydrocarbon free basis being suitable, may be added thru line 25`after which the diluted mixture may be conducted to a stripping column 21. Where secondary alcohols are being manufactured it is advantageous to provide for suitable hydrolysis of the alkyl esters as described, for example, in United States Patent 1,912,695, before distillation. In any case the acid may be removed from the alcohol or'alcohols present, as bottoms 28 from the stripping column while alcohol, water and any olefine regenerated in distillation'I are removed thru line 29 and condensed in condenser 30 which is suitably cooled by a refrigerant circulated therethru by means of inlet and outlet lines 33 and 34. Where amyl or higher alcohols are being produced the process of United States Patent 1,955,416 may be availed of as an alternative for the stripping procedure here described. In either case crude tertiary amyl alcohol containing water may be recovered as an upper layer withdrawn thru line 3, from a separator such as 3i, while an aqueous layer is taken off thru line 32 andadded to the other dilution water going to tank, 24. The crude tertiary amyl alcohol thus withdrawn is that ad- Since they are concentrated they must be blended with the feed in order to avoid the introduction of variable factors which make continuous operation extremely diiilcult. Mixing the crude amylene-pentane with the crude alcohols permits cony tinuous blending. of the hydrocarbons without resorting to elaborate proportioning devices which would otherwise be necessary. Furthermore if a dissimilar dehydrating agentsuch as hexane, benzene, or the like such as'has heretofore been employed, is used, the amylene must be distilled from the crude alcohol before dehydration, or the dehydrating agent must be separately'distilled to remove amylene therefrom, to avoid` contamination of the amylene returned to the reactor.

In either case, anextra distillation, which is rendered unnecessary by the process of our invention, is required.

. While our process has been described in connection with alcohols, particularly with the manufacture of one individual alcohol, tertiary amyl a1cohol,-it will be apparent that the processis not limited to suchapplications, since not only may it be applied to other individual alcohols of four or more carbon atoms, as has already been pointed out, but also it may be used for the production of mixtures of such alcohols, such, for example, as may be obtained, by absorbing a tertiary oleflne in an acid liquor produced by absorption of the corresponding'secondary olene in an aqueous mineral acid acting acid and dilution of the resulting solution as described and claimed. in our copending application Serial No. 734,118, 'flled July 7, 1934. Furthermore, other methods for converting oleflries to the corresponding alcohols, such, for example, as direct hydration procedures, etc., may be used. Not only may other olefine derivatives such as esters, ethers, halohydrins, and the like, but also similar or other derivatives of parafns and cyclic hydro- -carbons such, for example, as the acids, aldematter that the pressures involved when vusing ethylene and/or propylene fractions, for example, necessitate the use of such expensive distillation apparatus that we prefer to limit our process to the treatment of derivatives prepared from hydrocarbons containing substantial amounts of compounds of at least four carbon atoms per molecule. In its application to the production of secondary and/or tertiary alcohols vhaving four or more carbon atoms per molecule by absorption of the corresponding oleiines in a mineral acid acting medium, our invention has particular advantage however, because this reaction is an especially sensitive one in which careful control of the olene acid ratio must be maintained at all times in order to prevent oleflne regeneration. The ease of. blending of such regenerated olene with the feed which our process provides makes all steps in the process smoother, particularly under conditions of continuous operation with olene-paraflin mixtures.

Our process isnot only capable of many varied applications but also of many modications. It may be used 'in either continuous, intermittent or batch operations. In some cases it maybe l 2,100,437 advantageous to use only a part of the hydrocarmay be used as the dehydration agent. Still other changes such as will vbe apparent to .those smiled in the art may be made without departing from the spirit of our invention which is to be regarded as limited only by the terms of the accompanying claims, in which it is our intention to claim .all novelty inherent therein as possible in view of the prior art.

We claim as our invention:

l. In a process of producing a substantially an-l hydrous oxygen containing derivative' of an olefine having at least four carbon atoms per molecule', the steps ofremoving water from the aqueous derivative by mixing therewith hydrocarbon in the liquid state containing said oleilne, subsequently distiliing a. mixture of said derivative and said hydrocarbon to drive over water and said hydrocarbon, recovering the substantially dry oleilne derivative as bottom product and using the A olene containing hydrocarbon distilled off as a source of further olene derivative.

2. In a process of dehydrating anaqueous oxygen containing derivative of an oleiine having at least four carbon. atoms perA molecule in which a third `liquid miscible with the derivative but substantially immiscible with water .is added to the aqueous derivative tobe dehydrated and the mixture subjected to distillation to separate the third liquid and water from the derivative, ythe improvement which comprises supplying for saidV third liquid, the olene containing hydrocarbon,

to be subsequently used as the source of said derivative.

3. The process of producing dry alcohols having at least four carbon atoms per molecule from the corresponding olefines which comprises hydratlng an olene having at least four carbon atoms per molecule, extracting the resulting aqueous alcohol with a hydrocarbon mixture in the liquid state comprising said oleiine, distilling the extract,y

cohol solution by distilling ofi water therefrom with the olene containing hydrocarbon of at least four carbon atoms per molecule subsequently used in said absorption so as to obtain a concentrated alcohol residue.

5. In a process of producing a secondary alcohol of at least four carbon atoms per molecule by absorption of the corresponding oleiine in aqueous sulfuric acid and hydrolysis of the resulting alkyl sulfate solution the steps of dehydrating the substantially freeacid free aqueous alcohol, sub- -sequently obtained by distillation with secondary olenne containing hydrocarbon -of at least four, carbon atoms per molecule withoutsubstantially broadly as ing the resulting aqueous tertiary alcohol solul .tion by distllling ofi water therefrom with hydrocarbon of atleast four carbonatoms per molecule containing'said'tertiary olene so asto obtain a concentrated alcohol residue.

7. Ina process of producing a mixture of secondary and tertiary alcohols by absorptionvof 'thetertiary olefine content of a hydrocarbon mixture having the same number of carbon atoms per molecule and containing tertiary and secondary olenes in an acid liquor produced by absorption of said secondary olene in a mineral acid and dilution'of the resulting absorption product, the

step of dehydrating the aqueous alcohol mixture obtained as an intermediate product by distilling off water therefrom with said hydrocarbon mixture without substantially distilling ofi the alcohol content.

8. In a. process of producing tertiary and' secondary amyl alcohols by. absorbing at least a part of the tertiary and secondary amylene 4content of. a pentane-amylene fraction in aqueous sulfuric acid and subsequently separating a mixture of aqueous amyl alcohols from said acid, the steps of extracting said aqueous alcohol' mixture with a pentane-amylene fraction containing a substantial amount of secondary and tertiary amylenes and distilling the resulting extract to remove therefrom pentane-amylene mixture and water and leave as bottom product-substantially dry tertiary and secondary amyl alcohols.

9. In a process of producing secondary amyl alcohol by absorption of secondary amylenes from a pentane-amylene mixture substantially free of tertiary amylenes in aqueous sulfuric acid, hydrolysis of. the resulting amyl sulfates, and removal of free sulfuric acid, the steps of extracting the aqueous secondary amyl alcohol obtained with a pentane-amylene mixture and' distilling the resulting extract to remove therefrom pentaneamylene mixture and water and recovering substantially dry secondary amyl alcohol.

10. In a process of producing tertiary butyl alcohol by reaction of isobutyleney containing hydrocarbon of at least four carbon atoms per molecule with aqueous sulfuric acid, the steps of distilling the aqueous tertiary butyl alcohol obtained with said hydrocarbon to remove water therefrom and subsequently reacting the hydrocarbon used in said distillation to produce a further amount of tertiary butyl alcohol.

11. In a process of. producing an alcohol having at least four carbon atoms per molecule by absorption of the corresponding olenne in a mineral acid in which the absorption product is distilled to separate free acid from said alcohol the steps of condensing together oleiine regenarated and alcohol vaporized in said distillation and blending the mixture withfthe hydrocarbon feed to the System.

GERALD HENRY van n: GRIENDT. 

